Connection between a motor and a motor control circuit is made by connecting the motor with a control printed circuit board on which the motor control circuit is mounted. Here, for making connection between the motor and the control printed circuit board as a circuit board, a flexible printed circuit is used in many cases to reduce transfer of motor vibration to the control printed circuit board. Since the flexible printed circuit is securely connected to the control printed circuit board only at a soldered terminal portion in a mechanistic manner, the soldered portion tends to be subjected to any force when the flexible printed circuit is pulled due to motor vibration or external force application. Therefore, the soldered flexible printed circuit has been in danger of causing disconnection or fracture due to force applied in a direction of separating a copper wire or a copper foil, which is soldered on the terminal of the flexible printed circuit.
Various techniques, such as reinforcement fixation with adhesive tapes or adhesive agents, have been employed to prevent disconnection or fracture. However, in the case of using the adhesive tape, there are problems of an increase in cost for raw materials, an increase in cost for additional works such as stripping of release paper, generation of waste materials of release paper, and the like. Alternatively, in the case of using the adhesive agent, there are problems of unstable quality, difficulty in control of adhesive agents, time and facility requirements for dryness, tendency of the adhesive tape to adhere to an area other than adhesion-requiring areas, and the like.
A liquid crystal device disposed with a dummy terminal that does not participate in electric connection has been known to increase the connection reliability of a flexible printed circuit (see, for example, Japanese Unexamined Patent Application Publication No. 8-213721 (Patent Literature 1).
However, in Japanese Unexamined Patent Application Publication No. 8-213721 (Patent Literature 1), a thin-film dummy terminal printed on a flexible printed circuit is used. In this case, when more intense vibration, such as motor vibration, is applied to a connection portion compared with a liquid crystal device, the dummy terminal may be easily peeled off and then an electric connection terminal may be also peeled off. As a result, disconnection may occur.